rs137853225

Variant names:

• chr12-52676326-A-G
• rs137853225
• NM_006121.4:c.1424T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_006121.4(KRT1):​c.1424T>C​(p.Leu475Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: KRT1 NM_006121.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 9.25
• Publications: 1 publications found

Genes affected

KRT1 (HGNC:6412): (keratin 1) The protein encoded by this gene is a member of the keratin gene family. The type II cytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratin chains coexpressed during differentiation of simple and stratified epithelial tissues. This type II cytokeratin is specifically expressed in the spinous and granular layers of the epidermis with family member KRT10 and mutations in these genes have been associated with bullous congenital ichthyosiform erythroderma. The type II cytokeratins are clustered in a region of chromosome 12q12-q13. [provided by RefSeq, Jul 2008]

KRT1 Gene-Disease associations (from GenCC):

• annular epidermolytic ichthyosis

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Genomics England PanelApp, PanelApp Australia
• ichthyosis hystrix of Curth-Macklin

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Genomics England PanelApp, PanelApp Australia
• diffuse nonepidermolytic palmoplantar keratoderma

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
• epidermolytic ichthyosis

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Illumina, Orphanet, Genomics England PanelApp, PanelApp Australia
• ichthyosis, annular epidermolytic 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• ichthyosis, annular epidermolytic, 2

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
• congenital reticular ichthyosiform erythroderma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• striate palmoplantar keratoderma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal recessive congenital ichthyosis 11

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_006121.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.973

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KRT1	NM_006121.4	c.1424T>C	p.Leu475Pro	missense_variant	Exon 7 of 9	ENST00000252244.3	NP_006112.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KRT1	ENST00000252244.3	c.1424T>C	p.Leu475Pro	missense_variant	Exon 7 of 9	1	NM_006121.4	ENSP00000252244.3
KRT1	ENST00000548765.1	n.498T>C		non_coding_transcript_exon_variant	Exon 3 of 4	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Epidermolytic ichthyosis Pathogenic:1

Oct 01, 2002

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

KRT1-related disorder Uncertain:1

Sep 12, 2023

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The KRT1 c.1424T>C variant is predicted to result in the amino acid substitution p.Leu475Pro. This variant has been reported in individuals with epidermolytic ichthyosis or hyperkeratosis (Lee et al. 2002. PubMed ID: 12406348; Bygum et al. 2013. PubMed ID: 22930352). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Although we suspect that this variant may be pathogenic, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.94	D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.88	D
M_CAP	Pathogenic	0.67	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.1	H
PhyloP100		9.2
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-6.7	D
REVEL	Pathogenic	0.97
Sift	Uncertain	0.0040	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.80		Gain of catalytic residue at L477 (P = 2e-04);
MVP		0.98
MPC		1.2
ClinPred		1.0	D
GERP RS		4.8
Varity_R		0.97
gMVP		0.96
Mutation Taster		=1/99	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs137853225; hg19: chr12-53070110;